Automotive Air Conditioning Information Forum (Archives)

pek771 on Tue June 17, 2014 9:23 PM

Year: 1997
Make: Acura
Model: CL
Engine Size: 2.2
Refrigerant Type: R-134a
Ambient Temp: 85
Pressure Low: 80
Country of Origin: Japan

Hi all,
I am a bit baffled by a short cycle problem in the 97 Acura CL 2.2. The compressor short cycles very fast, as in 10 seconds fast, repeatedly. When first starting the car, it will stay on for maybe a minute, and the suction line will get cold. I can't get a good reading on vent temps, because the short cycling happens too fast for my thermometers to react. I can feel a pulse in the suction line whenever it short cycles, as though a solenoid valve were closing (much like the pulse from water hammer). I have no idea what sort of expansion device the car has.

If anyone knows the particulars of this system, I would appreciate your input.
TIA,
Pat


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Pat Keefe

GM Tech on Tue June 17, 2014 9:57 PM

More than likely your system has less than half the specified refrigerant amount in it--recover and weigh it to verify. Then find and fix your leak, evacuate and recharge to factory spec.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

pek771 on Tue June 17, 2014 11:04 PM

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Pat Keefe

pek771 on Tue June 17, 2014 11:06 PM

So, you seem to be saying there is some sort of pressure control which controls the cycling of the compressor? Low pressure, in this case?

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Pat Keefe

Jag987 on Tue June 17, 2014 11:34 PM

Yes, I think that is what he is implying. However, if the 80 on the low side is with the compressor running, the low side is too high. Is reading from a can refrigerant that came with a gauge? What it the pressure on the high side? If the 80 is with the system off (static pressure), it seems a little low for the temp listed.

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

mk378 on Tue June 17, 2014 11:56 PM

Does the condenser fan work? It is probably tripping off on high pressure, which you haven't measured. This is going to be a TXV system with the valve hidden in the evaporator box under the dash. If it's just that the fan doesn't start, you should get cold air with the car moving, which will force air through the condenser.

Edited: Wed June 18, 2014 at 12:01 AM by mk378

pek771 on Wed June 18, 2014 7:51 AM

Readings were done with my gauges. I am going to look at it again today, when the daughter gets home from school. The condenser fans cycle with the compressor, and it appears that all of the fan and compressor relays function OK. I believe the cause of the problem is whatever provides the signal for the compressor to stop and start. Is it a pressure switch, which would go to a relay? What causes the hammering in the suction line? I think I may be missing a relay somewhere.

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Pat Keefe

Jag987 on Wed June 18, 2014 9:25 AM

So what is the high side?

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

pek771 on Wed June 18, 2014 11:04 AM

OK, the pressures at start up were 240 high, 75 low. Ambient is 80. Within a minute the high pressure climbed steadily to 450, and low dropped to 50. When high gets to 460, it cuts out (which is probably what it should do).

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Pat Keefe

pek771 on Wed June 18, 2014 12:07 PM

I highly doubt the refrigerant charge is the cause of this. The original problem was the ac wasn't making cold air. I doubt half of the charge left the system, else it wouldn't make any cold air. I suspect a restriction somewhere.

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Pat Keefe

pek771 on Wed June 18, 2014 1:57 PM

I took some gas out of the system. High is around 230, unstable. Low is 35. System is functional but not optimal.

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Pat Keefe

mk378 on Wed June 18, 2014 4:58 PM

You should recover it all and then charge by weight to be sure of the correct amount. Also be careful of having too much oil. Has someone else worked on the car?